Facing the threat of prison, Duffy got his own lawyer and agreed to the man's defense strategy: Duffy needed to distance himself from Cahalane and Byrne. It would be an uphill battle, the man warned him, but Duffy ought to fight for a severed case, or at least claim that he had never purchased a gun for the IRA.

"He's a pacifist," a friend said of Duffy at the time to the newspapers. "He's been raising money for a Catholic glass factory in Derry. Based on a lot of knowledge, Dan Duffy has never been involved in anything illicit."

Not everyone had such harmless views of Duffy, though. Someone, clearly, was watching and didn't like what they saw.

Around the time of the indictment, Duffy's teenage daughter found a blank envelope stuffed in their mailbox. Inside was a note, with no return address. "You are brave enough to send the guns to kill others but not brave enough to stand up and do battle yourself," the note said. Tucked inside the fold of the envelope was a bullet, with a chilling message: "The next one is for you."

— Next One Is for You by Ali Watkins (63%)